You know what I'm going to add to this and I dont care if its a double post because it needs to be re-iterated. Raykz this isn't an attack on you, this is just how I see it in general when I watch many Mewtwo players opt for baby shadowball.
When you play Sheik, do you only ever fire single needles or do you go for the full stack?
When you play WFT, do you charge Sun Salutation all the way or shoot the tiny ones?
When you play Rob do you fire the uncharged gyro or do you wind it up?
When you play Wario do you use the waft at 30 seconds charged, or 90 seconds?
Choosing to use baby shadow balls is choosing to nerf your own character. You have the option of a weak move, or a strong move. This isn't the same as choosing to tilt instead of smash because the tilt is faster/safer since the higher charge SB is actually faster and safer!
If you watched someone play as any of those characters who consistently refused to charge their attacks you would note that its not a good strategy since the attack becomes far, far better when charged. Its safer, more damaging, more threatening and faster. Outside of a desperation 'get away from me' baby shadow ball to stop a dashing approach, baby shadow ball is an inferior option. Yes it can stuff approaches but why would you choose to stuff an approach with a slow 2% projectile when you can stuff it with a 10% or even 26% much faster projectile.
Treat it like Warios waft or Robs laser. Every single moment of gameplay where the enemy is not in your face, use this time to charge shadowball so the next time you throw one out to 'zone' the enemy, you are doing it with a much stronger attack.
Now directly @ you Raykz, I strongly feel that in your matches vs Sky your use of shadowball had gigantic room for improvement. I'm not telling you to justify your use of baby shadow balls or explain what zoning is to others, I'm saying that you should focus a lot on that. Take every opportunity you can to charge bigger shadowballs and make Sky SCARED. You have the strongest projectile in the game. By not using it, that's just as bad as Sky not using Yoshis aerials because he wants to zone with dtilt instead. That is literally how I see it, nerfing your own character.
I want to see Mewtwo mains do better and I bet my entire credibility on this forum with every theorycraft post I make. I don't write long posts like this, or that essay above, or make 15 minutes videos, because I'm some mad kid who cant beat a friends Samus spamming charge shot. I write this because I see a fundamentally good player with a big void in their gameplay who can work to fix it.
Of course, you have absolutely no reason to listen to what I am saying or change what you're doing, but I am very, very certain that with smarter shadowball use, your matches vs Sky are going to be very different. Just try it, whats the worst that could happen. I have no trouble admitting when I'm wrong and I don't spend hours labbing this stuff to make an idiot of myself on a forum.